Molybdenum-copper alloy spherical powder and preparation method thereof

Abstract

The invention discloses molybdenum-copper alloy spherical powder and a preparation method thereof, and relates to the technical field of alloy preparation, and the preparation method comprises the following steps: weighing molybdenum powder and copper powder, and uniformly mixing; molybdenum-copper mixed powder and absolute ethyl alcohol are added into a ball mill, and grinding balls are added for grinding; after grinding is completed, molybdenum-copper mixed powder is sieved and filled into a rubber sleeve, the rubber sleeve is placed in an isostatic pressing forming device for pressurization, a rubber plug is taken down after pressurization is completed, and a molybdenum-copper bar blank is taken out; placing the molybdenum-copper rod blank in an aluminum oxide ceramic boat, and sintering in a high-temperature furnace; after sintering is completed, turning an external thread at one end of the molybdenum-copper bar blank to obtain a molybdenum-copper alloy bar; molybdenum-copper alloy bars are assembled on a material feeder of a rotating electrode atomization device, protective atmosphere is filled, molybdenum-copper alloy powder is collected after the process is finished, the molybdenum-copper alloy spherical powder is obtained through screening, and the molybdenum-copper alloy spherical powder is regular in surface appearance, few in defect, few in agglomeration, narrow in particle size distribution, high in sphericity degree and free of obvious layered, interface or segregation problems.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy preparation, and particularly relates to a molybdenum-copper alloy spherical powder and a preparation method thereof. Background Art

[0002] Composite powder is a material made by mixing two or more powders through physical or chemical methods. Compared with single powder, it usually has different physical and chemical properties and can achieve performance that is difficult to achieve with single powder. Spherical composite powder has better fluidity and filling properties, is more likely to form a dense structure, reduce porosity, and improve the mechanical properties of the material.

[0003] Molybdenum-copper (Mo-Cu) composite powders combine the excellent properties of both Mo and Cu, exhibiting excellent thermal conductivity, electrical conductivity, high-temperature performance, thermal expansion coefficient, and machinability. They are currently important functional materials in fields such as optoelectronics, aerospace, and new energy materials and devices. They are widely used as electronic packaging and heat sink materials for semiconductor devices, structural components for new energy vehicle power systems, armor-piercing materials for liner materials, and high-temperature sweating materials for aerospace applications, and have great application prospects. However, due to the significant difference in the melting points of Mo and Cu, they cannot form solid solutions or intermetallic compounds. Mo-Cu alloys are therefore considered "pseudoalloys" and are currently typically prepared using powder metallurgy processes. The patent "CN 117051283 A, publication date November 14, 2023" discloses a low-molybdenum-content molybdenum-copper alloy and its preparation method. By mixing molybdenum powder and copper powder, pressing them into a specific shape and then sintering them, a molybdenum-copper alloy powder with a low molybdenum content is obtained; the patent "CN115229202A, publication date October 25, 2022" discloses a preparation method for molybdenum-copper nanocomposite powder. Ammonium molybdate is used as a raw material, and highly active amorphous carbon nanoparticles are used as nucleating agents for the decomposition of ammonium molybdate. Molybdenum dioxide and molybdenum composite powders are obtained through mixing, drying, and thermal decomposition steps. The copper salt is dispersed in ethanol added with the composite powder and ultrasonically atomized. After high-temperature reduction, nano-molybdenum-copper composite powders with small particle size and loose structure are obtained. Patent CN118455529A, published on August 9, 2024, discloses a method for preparing molybdenum-copper alloy powder. Using molybdenum powder and copper powder as raw materials, spherical Mo-Cu alloy powder is produced through discharge plasma solid-phase sintering and plasma rotating electrode atomization. The Mo-Cu composite powder prepared by this method has a rough surface morphology, lacks mutual dissolution or metallurgical composite, and has an uneven distribution of molybdenum and copper phases. The powder is merely mechanically entangled, failing to form a cohesive alloy powder. Furthermore, the powder has poor sphericity, a wide particle size distribution, and poor mechanical properties, making it unsuitable for additive manufacturing. Summary of the Invention

[0004] The object of the present invention is to provide a molybdenum-copper alloy spherical powder and a preparation method thereof, so as to solve the problems of uneven distribution of molybdenum phase and copper phase, poor sphericity, wide particle size distribution and poor mechanical properties of the existing molybdenum-copper alloy spherical powder.

[0005] The technical solution adopted by the present invention is a method for preparing molybdenum-copper alloy spherical powder, comprising the following steps:

[0006] S1. Weigh molybdenum powder and copper powder and mix them evenly;

[0007] S2. Add molybdenum-copper mixed powder and anhydrous ethanol into a ball mill, add grinding balls and grind, and continuously introduce a protective atmosphere during the grinding process;

[0008] After S3 and grinding are completed, the molybdenum-copper mixed powder is sieved and loaded into a rubber sleeve, and a molybdenum rod is used to fill the powder and tamp it. During the tamping process, a rubber hammer is used to knock along the outer wall of the rubber tube and vibrate it. After tamping, a rubber plug is inserted into the end of the rubber sleeve and sealed. It is placed in an isostatic pressing device and pressurized. After reaching the setting pressure, pressure is maintained. After the pressure maintenance ends, the rubber plug is removed and the molybdenum-copper rod blank is taken out.

[0009] S4, placing the molybdenum-copper rod blank in an alumina ceramic boat, placing copper material on the molybdenum-copper rod blank, and placing the alumina ceramic boat in a high-temperature furnace for sintering;

[0010] S5. After sintering, the molybdenum-copper rod blank is placed on a lathe, one end of which is turned into an external thread, and the surface oxides and dirt are polished to obtain a molybdenum-copper alloy rod;

[0011] S6. Assemble the molybdenum-copper alloy rod onto the material feeder of the rotary electrode atomizer, evacuate the atomizer of the rotary electrode atomizer, and fill it with a protective atmosphere. Start the motor of the material feeder to increase the speed, start the plasma gun, and push the molybdenum-copper alloy rod to the bottom end, then the powder making is completed. After the powder making chamber cools down, the molybdenum-copper alloy powder is collected.

[0012] S7. Sieve the molybdenum-copper alloy powder on a vibrating sieving machine, collect the powder on the sieving net, and obtain spherical molybdenum-copper alloy powder.

[0013] Furthermore, in step S1, the molybdenum powder is 50-90 parts by mass, the copper powder is 10-50 parts by mass, the copper powder has a particle size of 60-100 microns, and the molybdenum powder has a particle size of 5-10 microns.

[0014] Furthermore, in step S2, the anhydrous ethanol is 2-4 parts by mass, the protective atmosphere is nitrogen or argon, and the protective atmosphere is introduced at a pressure of 1-5 MPa.

[0015] Furthermore, in step S3, the pressurization rate of the isostatic pressing device is 8-10 MPa / min, the set pressure is 350-450 MPa, and the holding time is 3-5 min.

[0016] Furthermore, in step S4, the sintering temperature is 1350-1380° C., the copper material is 12-60 parts by mass, the sintering temperature heating rate is 8-10° C. / min, and the sintering time is 1.5-2 h.

[0017] Furthermore, in step S6, the protective atmosphere is argon, the operating current of the plasma gun is 800-1600A, and the motor speed of the material feeder is 17000-19000r / min.

[0018] Furthermore, in step S7, the vibration screening device includes four groups of screening meshes with mesh sizes of 100 mesh, 170 mesh, 240 mesh and 325 mesh respectively, the screening time is 10-15 minutes, and the vibration frequency of the screening mesh is 25-35 times / minute.

[0019] Another technical solution adopted by the present invention is a molybdenum-copper alloy spherical powder obtained according to the preparation method of the molybdenum-copper alloy spherical powder of the present invention.

[0020] The beneficial effects of the present invention are:

[0021] (1) The molybdenum-copper alloy spherical powder prepared by the present invention has a regular surface morphology, few defects, little agglomeration, a narrow particle size distribution, high sphericity, no obvious laminar, interface or segregation problems, and has very high hardness.

[0022] (2) The present invention utilizes isostatic pressing and infiltration sintering technology to prepare molybdenum-copper rod blanks, and the organization, density, and composition of each part thereof are evenly distributed, which can ensure that the composition ratio of the molybdenum and copper phases remains unchanged during subsequent local melting.

[0023] (3) The present invention prepares molybdenum-copper alloy spherical powder by using a rotating electrode atomization device. The plasma gun can strike an arc at the top of the prefabricated molybdenum-copper rod, instantly generating an extremely high temperature to melt its surface, and ejecting fine droplets under the action of high-speed centrifugation. During the rapid cooling process, the molybdenum and copper phases are stably and uniformly combined. High-quality molybdenum-copper alloy spherical powder with high sphericity, narrow particle size distribution and no hollow powder can be obtained. The powder is suitable for subsequent 3D printing, powder metallurgy, high entropy alloy and other processing technologies, and has broad application prospects.

[0024] (4) The present invention uses zone melting technology to achieve the preparation of molybdenum-copper alloys with extremely different melting points and densities, which solves the problem that traditional smelting technology cannot simultaneously melt molybdenum and copper, resulting in uneven distribution of the two phases. It can not only ensure the structural density of the molybdenum-copper alloy, but also is beneficial to the stability of the material. The preparation process is simple and efficient, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a physical picture of the molybdenum-copper rod blank prepared in Example 1 of the present invention;

[0027] Figure 2 Schematic diagram of the plasma rotating electrode atomization method for powder production according to the present invention;

[0028] Figure 3 Schematic diagram of a vibrating screening machine of the present invention;

[0029] Figure 4 This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Example 1 of the present invention;

[0030] Figure 5 This is the EDS spectrum of the molybdenum-copper alloy spherical powder prepared in Example 4 of the present invention;

[0031] Figure 6 The XRD pattern of the molybdenum-copper alloy spherical powder prepared in Example 4 of the present invention;

[0032] Figure 7 This is the load-displacement curve of the molybdenum-copper alloy spherical powder prepared in Example 3 of the present invention;

[0033] Figure 8 This is the SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 1 of the present invention. Figure 8 (a1) Scale bar is 10 μm. Figure 8 (a2) Scale bar is 1 μm;

[0034] Figure 9 This is the SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 2 of the present invention. Figure 9 (b1) Scale bar is 10 μm. Figure 9 (b2) Scale bar is 1 μm;

[0035] Figure 10This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 3 of the present invention;

[0036] Figure 11 This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 4 of the present invention;

[0037] Figure 12 This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 5 of the present invention;

[0038] Figure 13 This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 6 of the present invention;

[0039] Figure 14 This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 7 of the present invention;

[0040] Figure 15 This is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 8 of the present invention;

[0041] In the accompanying drawings, 1 is a material feeder, 2 is a molybdenum-copper alloy rod, 3 is a molybdenum-copper alloy powder, 4 is a plasma gun, 5 is a dust cover, 6 is a screening machine housing, 7 is a discharge port, 8 is a power device, 9 is a base, 10 is a feed port, 11 is a screening net (the mesh numbers from top to bottom are 100 mesh, 170 mesh, 240 mesh and 325 mesh respectively), 12 is a bottom frame, and 13 is a shock-absorbing spring. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] Example 1

[0044] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder comprises the following steps:

[0045] S1. Weigh 50 parts of molybdenum powder and 50 parts of copper powder by mass and mix them evenly. The purity of the molybdenum powder and the copper powder are both 99%, the particle size of the copper powder is 60 μm, and the particle size of the molybdenum powder is 5 μm.

[0046] S2. Add 100 parts by mass of molybdenum-copper mixed powder and 2 parts of anhydrous ethanol to a ball mill, add grinding balls and grind. During the grinding process, nitrogen is passed as a protective atmosphere. The nitrogen pressure is 1 MPa and the atmosphere is replaced every half hour. The grinding balls are molybdenum balls with a diameter of 3 to 8 mm. The volume ratio of grinding balls to molybdenum-copper mixed powder is 5:1. The grinding speed is 550 rpm and the grinding time is 3 hours.

[0047] S3, after grinding is completed, the molybdenum-copper mixed powder is passed through a 40-mesh sieve and loaded into a rubber sleeve. The inner diameter of the rubber sleeve is 30mm and the length is 150mm. The powder is filled and tamped using a molybdenum rod. The tamping rod should go deep into the powder each time it is tamped. After each tamping, it is tapped 5-10 times along the outer wall of the rubber sleeve with a rubber hammer for compaction. After tamping, a rubber plug is inserted into the end of the rubber sleeve and sealed with iron wire. It is placed in an isostatic pressing device for pressurization. The pressure is set to 350MPa and the pressure increase rate is 8MPa / min. After reaching the set pressure, the pressure is maintained for 3min. After the pressure is maintained, the rubber plug is removed and the molybdenum-copper rod blank is taken out.

[0048] S4. Place the molybdenum-copper rod blank in an alumina ceramic boat, place copper material on the molybdenum-copper rod blank, and place 60 parts by mass of copper material on the molybdenum-copper rod blank. Place the alumina ceramic boat in a high-temperature furnace for sintering. The atmosphere in the high-temperature furnace is argon. Set the sintering temperature to 1350°C and the heating rate to 8°C / min. After reaching the sintering temperature, keep the temperature for 1.5 hours. After the high-temperature furnace is cooled to room temperature, take out the molybdenum-copper rod blank and cut off the excess copper material on the surface of the rod blank.

[0049] S5. After sintering, the molybdenum-copper rod blank is placed on a lathe, and an external thread is turned on one end thereof. The external thread parameter is M16×1.5 mm, and the surface oxides and dirt are removed by grinding to obtain a molybdenum-copper alloy rod;

[0050] S6. Assemble the molybdenum-copper alloy rod on the material feeder 1 of the rotary electrode atomizer, leaving 5 cm of the powder making chamber hole exposed. Evacuate the atomizer of the rotary electrode atomizer to a vacuum degree of 8×10 -2 Pa, flush with 99% pure argon until the internal pressure of the powder making chamber reaches 1atm, repeat three times. Start the motor of material feeder 1 and increase the speed to 20,000r / min. Start plasma gun 4, set the current to 650A, and set the rod pushing speed to 1.3mm / s. When the molybdenum-copper alloy rod reaches the bottom, the powder making is completed. After the powder making chamber cools down, remove the powder box and collect the molybdenum-copper alloy powder on the cabin wall;

[0051] S7. The molybdenum-copper alloy powder is sieved on a vibrating sieving machine. The vibrating sieving machine is provided with four groups of sieve meshes 11, namely 100 mesh, 170 mesh, 240 mesh and 325 mesh. The vibration frequency of the sieve mesh 11 is 25 times / minute, and the vibration time is 10 min. The powder on each sieve mesh 11 except the 100 mesh is collected to obtain a spherical molybdenum-copper alloy powder.

[0052] Example 2

[0053] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder is disclosed. The method differs from Example 1 in that, in this embodiment, the molybdenum powder is 60 parts, the copper powder is 40 parts, and the copper material is 48 parts, calculated by mass; the copper powder particle size is 70 microns, and the molybdenum powder particle size is 6 microns; the protective atmosphere pressure is 2 MPa; the isostatic pressing device pressure is set to 380 MPa, and the holding time is 4 minutes; the sintering temperature is 1360°C, the sintering time is 1.5 hours, the motor speed of the material feeder 1 is 17000 rpm, the operating current of the plasma gun 4 is 1000 A, the screening time is 10 minutes, and the vibration frequency of the screening net 11 is 25 times / minute.

[0054] Example 3

[0055] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder is disclosed. The method differs from Example 1 in that, in this embodiment, the molybdenum powder is 70 parts, the copper powder is 30 parts, the copper material is 36 parts, and the anhydrous ethanol is 3 parts, by mass; the copper powder particle size is 80 microns, and the molybdenum powder particle size is 7 microns; the protective atmosphere pressure is 3 MPa; the isostatic pressing device is set to a pressurization rate of 9 MPa / min, a set pressure of 400 MPa, and a holding time of 4 minutes; the sintering temperature is 1360°C, the motor speed of the material feeder 1 is 17000 r / min, the operating current of the plasma gun 4 is 1000 A, the screening time is 10 minutes, and the vibration frequency of the screening net 11 is 25 times / minute.

[0056] Example 4

[0057] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder is disclosed. The method differs from Example 1 in that, in this embodiment, the molybdenum powder is 80 parts, the copper powder is 20 parts, the copper material is 24 parts, and the anhydrous ethanol is 4 parts, calculated by mass; the copper powder particle size is 90 microns, and the molybdenum powder particle size is 8 microns; the protective atmosphere is argon, and the air pressure is 4 MPa; the isostatic pressing device is set to a pressurization rate of 10 MPa / min, a set pressure of 420 MPa, and a holding time of 4 minutes; the sintering temperature is 1370°C, the heating rate is 10°C / min, the sintering time is 2 hours, the motor speed of the material feeder 1 is 19000 r / min, the operating current of the plasma gun 4 is 1400 A, the screening time is 15 minutes, and the vibration frequency of the screening net 11 is 35 times / minute.

[0058] Example 5

[0059] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder is disclosed. The method differs from Example 1 in that, in this embodiment, the molybdenum powder is 90 parts, the copper powder is 10 parts, the copper material is 12 parts, and the anhydrous ethanol is 4 parts, calculated by mass; the copper powder particle size is 100 microns, and the molybdenum powder particle size is 9 microns; the protective atmosphere is argon, and the air pressure is 5 MPa; the isostatic pressing device is set to a pressurization rate of 10 MPa / min, a set pressure of 450 MPa, and a holding time of 4 minutes; the sintering temperature is 1380°C, the heating rate is 10°C / min, the sintering time is 2 hours, the motor speed of the material feeder 1 is 19000 r / min, the operating current of the plasma gun 4 is 1600 A, the screening time is 15 minutes, and the vibration frequency of the screening net 11 is 35 times / minute.

[0060] Example 6

[0061] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder is disclosed. The method differs from Example 1 in that, in this embodiment, the molybdenum powder is 90 parts, the copper powder is 10 parts, the copper material is 12 parts, and the anhydrous ethanol is 3 parts, calculated by mass; the copper powder particle size is 60 microns, and the molybdenum powder particle size is 10 microns; the protective atmosphere is argon, and the air pressure is 5 MPa; the isostatic pressing device is set to a pressurization rate of 9 MPa / min, a set pressure of 400 MPa, and a holding time of 4 minutes; the sintering temperature is 1350°C, the heating rate is 10°C / min, the sintering time is 2 hours, the motor speed of the material feeder 1 is 17000 r / min, the operating current of the plasma gun 4 is 1600 A, the screening time is 15 minutes, and the vibration frequency of the screening net 11 is 30 times / minute.

[0062] Example 7

[0063] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder is different from Example 1 in that, in this embodiment, the amount of anhydrous ethanol is 4 parts by mass; the copper powder particle size is 100 microns, and the molybdenum powder particle size is 10 microns; the protective atmosphere is argon, and the air pressure is 5 MPa; the isostatic pressing device is set to a pressurization rate of 10 MPa / min, a set pressure of 450 MPa, and a holding time of 4 minutes; the sintering temperature is 1380°C, the heating rate is 10°C / min, the sintering time is 2 hours, the motor speed of the material feeder 1 is 19000 r / min, the operating current of the plasma gun 4 is 1000 A, the screening time is 15 minutes, and the vibration frequency of the screening net 11 is 35 times / minute.

[0064] Example 8

[0065] A method for preparing Mo-Cu molybdenum-copper alloy spherical powder, which differs from Example 1 in that the copper powder particle size in this embodiment is 70 microns, and the molybdenum powder particle size is 6 microns; the protective atmosphere is argon, and the air pressure is 2 MPa; the isostatic pressing pressure is set to 350 MPa, and the holding time is 4 minutes; the sintering temperature is 1360°C, the motor speed of the material feeder 1 is 18000 r / min, the operating current of the plasma gun 4 is 1000 A, the screening time is 10 minutes, and the vibration frequency of the screening net 11 is 25 times / minute.

[0066] Comparative Example 1

[0067] The difference from Example 3 is that the copper powder particle size is 30 microns, the molybdenum powder particle size is 3 microns, and the other steps are the same.

[0068] Comparative Example 2

[0069] The difference from Example 3 is that the copper powder particle size is 20 microns, the molybdenum powder particle size is 20 microns, and the other steps are the same.

[0070] Comparative Example 3

[0071] The difference from Example 2 is that the motor speed of the material feeder 1 is 16000 r / min, the working current of the plasma gun 4 is 700 A, and the other steps are the same.

[0072] Comparative Example 4

[0073] The difference from Example 3 is that the sintering temperature in step S4 is set to 1390° C., and the other steps are the same.

[0074] Comparative Example 5

[0075] The difference from Example 3 is that the sintering temperature in step S4 is set to 1200° C., and the other steps are the same.

[0076] Comparative Example 6

[0077] The difference from Example 1 is that no copper material is added in step S4, and the other steps are the same.

[0078] Comparative Example 7

[0079] The difference from Example 4 is that no isostatic pressing device is used in step S3, and the other steps are the same.

[0080] Comparative Example 8

[0081] The difference from Example 1 is that the motor speed of the material feeder 1 is 20000 r / min, the working current of the plasma gun 4 is 1700 A, and the other steps are the same.

[0082] Table 1 Ratio of molybdenum-copper powders with different compositions and copper material quality

[0083] Alloy composition <![CDATA[Theoretical density (g / cm 3 )]]> <![CDATA[Actual density (g / cm 3 )]]> <![CDATA[Copper material quality (g / cm 3 )]]> Mo50-Cu50 9.506 8.12 1.72 Mo60-Cu40 9.638 8.23 1.74 Mo70-Cu30 9.771 8.33 1.76 Mo80-Cu20 9.911 8.45 1.49 Mo90-Cu10 10.052 8.55 1.13

[0084] According to Table 1, there is a certain gap between the theoretical density and the actual density of different molybdenum-copper alloy components. If no additional copper material is added during the sintering process, the density of the prepared molybdenum-copper rod blank will be low and cannot meet the requirements of the alloy powder. The present invention supplements the corresponding copper material according to the actual density to meet the density requirements of the molybdenum-copper alloy.

[0085] like Figure 1 As shown, the molybdenum-copper rod blank prepared in Example 1 of the present invention is shown. It can be seen that the color distribution of each part of the molybdenum-copper rod blank prepared in the present invention is uniform. During the preparation process, the organization and composition distribution of molybdenum and copper inside the rod blank are very uniform, and no stratification or segregation occurs.

[0086] like Figure 2 As shown, it is a schematic diagram of the plasma rotating electrode atomization method for powder production according to the present invention. The plasma rotating electrode device includes a material feeder 1 and a plasma gun 4. The molybdenum-copper alloy rod 2 is fixed on the material feeder 1. The plasma gun 4 can strike an arc at the top of the molybdenum-copper alloy rod 2, instantly generating an extremely high temperature to melt its surface, ejecting fine droplets under the action of high-speed centrifugation, and generating molybdenum-copper alloy powder 3 during the rapid cooling process, thereby achieving stable and uniform combination of the molybdenum and copper phases.

[0087] like Figure 3 As shown, a schematic diagram of the vibrating screening machine of the present invention is shown, which includes a dust cover 5, a screening machine housing 6, a discharge port 7, a power device 8, a base 9, a feed port 10, a screening mesh 11 (the mesh numbers from top to bottom are 100 mesh, 170 mesh, 240 mesh and 325 mesh), a bottom frame 12, and a shock-absorbing spring 13; screening the molybdenum-copper alloy spherical powder can meet the use requirements of various fields, and the average particle size of the molybdenum-copper alloy spherical powder obtained by the vibrating screening machine is 50 to 80 microns, and this particle size range is more conducive to additive manufacturing.

[0088] like Figure 4 As shown, this is an SEM image of the molybdenum-copper alloy spherical powder prepared in Example 1 of the present invention. The motor speed of the plasma rotary motor atomizing device and the current of the plasma gun 4 have a great influence on the sphericity of the molybdenum-copper alloy spherical powder. In Example 1 of the present invention, when the working current of the plasma gun 4 is set to 650A and the motor speed is 20000r / min, the molybdenum-copper alloy spherical powder prepared has a full appearance, a uniform distribution of molybdenum phase and copper phase, a sphericity of 0.95-0.98, an average particle size of 50 microns, and a narrow particle size distribution range.

[0089] like Figure 5 As shown, this is the EDS spectrum of the molybdenum-copper alloy spherical powder prepared in Example 5 of the present invention. Figure 6From the XRD spectrum, it can be seen that the prepared molybdenum-copper alloy spherical powder is mainly composed of molybdenum and copper, with very few other impurities. It has extremely high purity and uniformity, and is more conducive to the manufacture of high-performance materials.

[0090] like Figure 7 As shown in FIG, the nanoindentation load-displacement curve of the molybdenum-copper alloy spherical powder prepared in Example 3 of the present invention shows that the powder has excellent mechanical properties, with a maximum load of 50 mN and a corresponding hardness of 471 MPa.

[0091] like Figure 8 , which is a SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 1 of the present invention, Figure 8 (a1) Scale bar is 10 μm. Figure 8 (a2) The scale bar is 1 μm. It can be seen that if the copper powder particle size is 30 μm, it is difficult to form a spherical shape during the preparation process;

[0092] like Figure 9 , which is a SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 2 of the present invention, Figure 9 (b1) Scale bar is 10 μm. Figure 9 (b2) The scale bar is 1 μm. It can be seen that if the copper powder particle size is 20 μm and the molybdenum powder particle size is 20 μm, it is difficult to form a spherical shape during the preparation process;

[0093] like Figure 10 As shown, it is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 3 of the present invention. It can be seen that the molybdenum-copper alloy powder prepared under the setting conditions of the comparative example has poor sphericity, and some of the powders do not obtain sphericity.

[0094] like Figure 11 As shown, it is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 4 of the present invention. It can be seen that the sphericity of the molybdenum-copper alloy powder prepared under the setting conditions of the comparative example is poor.

[0095] like Figure 12 As shown, it is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 5 of the present invention. It can be seen that the molybdenum-copper alloy powder prepared under the setting conditions of the comparative example is almost difficult to be formed.

[0096] like Figure 13 As shown, it is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 6 of the present invention. It can be seen that the molybdenum-copper alloy powder prepared without adding copper material has a loose structure and cannot form a sphere.

[0097] like Figure 14 As shown, it is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 7 of the present invention. It can be seen that the surface of the molybdenum-copper alloy spherical powder that has not been pressed is rough, the density is poor, and the sphericity is low.

[0098] like Figure 15, which is an SEM image of the molybdenum-copper alloy spherical powder prepared in Comparative Example 8 of the present invention. It can be seen that under this condition, the molybdenum powder of the molybdenum-copper alloy powder is almost adhered together and does not form a sphere.

[0099] Each embodiment in this specification is described in a related manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiment is generally similar to the method embodiment, so the description is relatively simple. For related parts, refer to the description of the method embodiment.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for preparing spherical powder of molybdenum-copper alloy, characterized in that: The following steps are involved: S1. Weigh molybdenum powder and copper powder and mix them evenly; S2, adding molybdenum-copper mixed powder and anhydrous ethanol into a ball mill, adding grinding balls for grinding, and continuously introducing a protective atmosphere during the grinding process; S3. After grinding, the molybdenum-copper mixed powder is sieved and loaded into a rubber sleeve. The powder is filled and compacted using a molybdenum rod. During the compaction process, a rubber hammer is used to knock along the outer wall of the rubber sleeve for compaction. After compaction, a rubber plug is inserted into the end of the rubber sleeve and sealed. The rubber sleeve is placed in an isostatic pressing device for pressurization. After reaching the set pressure, the pressure is maintained. After the pressure maintenance is completed, the rubber plug is removed and the molybdenum-copper rod blank is taken out; S4, placing the molybdenum-copper rod in an alumina ceramic boat, placing copper material on the molybdenum-copper rod, and placing the alumina ceramic boat in a high-temperature furnace for sintering; S5. After sintering, the molybdenum-copper rod blank is placed on a lathe, one end of which is turned into an external thread, and the surface oxides and dirt are removed by grinding to obtain a molybdenum-copper alloy rod; S6, assembling the molybdenum-copper alloy rod onto the material feeder (1) of the rotary electrode atomization device, evacuating the atomization furnace of the rotary electrode atomization device and filling it with a protective atmosphere, starting the motor of the material feeder (1) to increase the speed, starting the plasma gun (4), and the molybdenum-copper alloy rod is pushed to the bottom end, and the powder making is completed. After the powder making chamber is cooled, the molybdenum-copper alloy powder is collected; S7, sieving the molybdenum-copper alloy powder on a vibrating sieving machine, collecting the powder on the sieving net (11), and obtaining molybdenum-copper alloy spherical powder.

2. The method for preparing a molybdenum-copper alloy spherical powder according to claim 1, characterized in that: In step S1, the molybdenum powder is 50-90 parts by mass, the copper powder is 10-50 parts by mass, the copper powder has a particle size of 60-100 microns, and the molybdenum powder has a particle size of 5-10 microns.

3. The method for preparing a molybdenum-copper alloy spherical powder according to claim 1, characterized in that: In step S2, the anhydrous ethanol is 2-4 parts by mass, the protective atmosphere is nitrogen or argon, and the protective atmosphere is introduced at a pressure of 1-5 MPa.

4. The method for preparing a molybdenum-copper alloy spherical powder according to claim 1, characterized in that: In step S3, the pressure rate of the isostatic pressing device is 8-10 MPa / min, the set pressure is 350-450 MPa, and the holding time is 3-5 min.

5. The method for preparing a molybdenum-copper alloy spherical powder according to claim 1, characterized in that: In step S4, the copper material is 12-60 parts by mass, the sintering temperature is 1350-1380° C., the sintering temperature heating rate is 8-10° C. / min, and the sintering time is 1.5-2 h.

6. The method for preparing a molybdenum-copper alloy spherical powder according to claim 1, characterized in that: In step S6, the protective atmosphere is argon, the motor speed of the material feeder (1) is 17000-19000 r / min, and the working current of the plasma gun (4) is 800-1600 A.

7. The method for preparing a molybdenum-copper alloy spherical powder according to claim 1, characterized in that: In step S7, the vibrating screening machine comprises four groups of screening nets (11), the mesh sizes of which are 100 mesh, 170 mesh, 240 mesh and 325 mesh respectively, the screening time is 10-15 minutes, and the vibration frequency of the screening nets (11) is 25-35 times / minute.

8. A molybdenum-copper alloy spherical powder, characterized in that: The method for preparing the molybdenum-copper alloy spherical powder according to any one of claims 1 to 7 is obtained.

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